Verstappen, H. Th.
A geomorphological reconnaissance of Sumatra and adjacent islands (Indonesia) / H. Th. Verstappen
Wolters-Noordhoff , 1973
 Buku Teks
The Far Eastern Quarterly : review of Eastern Asia and the adjacent Pacific Islands
New York : The Far Eastern Assocation, Inc
 Majalah, Jurnal, Buletin
Wilcocks, Julie
Countries and islands of the world: a guide to nomenclature
Clive Bincley, 1985
 Buku Referensi
Vira, Raghu
A dictionary of English-Indian Terms of administration
International Academy of Indian Culture, 1950
 Buku Referensi
Vira, Raghu
The consolidated great English-Indian dictionary of technical terms
Secretary The International Academy of Indian Culture, 1950
 Buku Referensi